Susan Powell's Dad Asks, 'Why Didn't You Arrest Him?'

His apparent attraction to his daughter-in-law has been raised before. In a 2011 interview with "Good Morning America," he said he had a flirtatious relationship with her that went "a little beyond the pale."

He described the relationship as "father-in-law-daughter-in-law flirting with each other, maybe some sexual touching or whatever."

"There's no question in my mind that the feelings were mutual," he said.

Cox, Susan Powell's father, said that he had wanted to protect his grandchildren, but now that they're gone, he just wants to find his daughter.

"We let the police do their investigation and hope that sometime we'll be able to talk to Steve Powell and he'll be able to tell her where she is if he knows."

Josh Powell has long been a suspect in his wife's disappearance, beginning with the police's initial search of the West Valley City, Utah, home the two shared with their boys. There, investigators found two fans drying a wet area on the rug where a red stain had been removed.

Josh Powell said that his wife had been cleaning the rug before she disappeared. He also told authorities that he had decided take an impromptu midnight camping trip with the boys in the midst of a blizzard, the night his wife vanished. Powell said he returned home to find his wife gone.

Later, he would blame his wife's mental state -- "extremely unstable" -- for her disappearance, while his father maintained she had skipped town with a man who disappeared from a Christmas party the night she vanished.